This weekend we (Lars and I) finished our first public alpha release of Subplot. Subplot is a tool for helping you to document your acceptance criteria for a project in such a way that you can also produce a programmatic test suite for the verification criteria. We centre this around the concept of writing a Markdown document about your project, with the option to write Gherkin-like given/when/then scenarios inside which detail the automated verification of the acceptance criteria.

This may sound very similar to Yarn, a similar concept which Lars, Richard, and I came up with in 2013. Critically back then we were very 'software engineer' focussed and so Yarn was a testing tool which happened to also produce reasonable documentation outputs if you squinted sideways and tried not to think too critically about them. Subplot on the other hand considers the documentation output to be just as important, if not more important, than the test suite output. Yarn was a tool which ran tests embedded in Markdown files, where Subplot is a documentation tool capable of extracting tests from an acceptance document for use in testing your project.

The release we made is the first time we're actively asking other people to try Subplot and see whether the concept is useful to them. Obviously we expect there to be plenty of sharp corners and there's a good amount of functionality yet to implement to make Subplot as useful as we want it to be, but if you find yourself looking at a project and thinking "How do I make sure this is acceptable to the stakeholders without first teaching them how to read my unit tests?" then Subplot may be the tool for you.

While Subplot can be used to produce test suites with functions written in Bash, Python, or Rust, the only language we're supporting as first-class in this release is Python. However I am personally most interested in the Rust opportunity as I see a lot of Rust programs very badly tested from the perspective of 'acceptance' as there is a tendency in Rust projects to focus on unit-type tests. If you are writing something in Rust and want to look at producing some high level acceptance criteria and yet still test in Rust, then please take a look at Subplot, particularly how we test subplotlib itself.

Issues, feature requests, and perhaps most relevantly, code patches, gratefully received. A desire to be actively involved in shaping the second goal of Subplot even more so.